title: Asymmetric synthesis of pyrrolo[2,1-a]isoquinoline derivatives by 1,3-dipolar cycloadditions of stabilized isoquinolinium N-ylides with sulfinyl dipolarophiles.
abstract: Enantiomerically pure pyrrolo[2,1-a]isoquinoline derivatives are obtained by 1,3-dipolar reactions of isoquinolinium azomethine ylides with enantiopure 3-p-tolylsulfinylacrylonitriles, tert-butyl (2E)-4,4-diethoxy-2-p-tolylsulfinylbut-2-enoate, and 5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones. Reactions evolve through the anti conformation of the ylide with complete regioselectivity. The facial selectivity is completely controlled by the configuration of the sulfinyl sulfur for acyclic dipolarophiles, whereas it is high (dr 83/17 or 89/11) but controlled by the C-5 configuration for sulfinylfuranones. Complete endo selectivity is observed with cyclic dipolarophiles and substituted acrylonitriles, but it is low with butenoate. The sulfinyl group also exerts a positive influence on the dipolarophilic reactivity toward these ylides.
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain. joseluis.garcia.ruano@uam.es
authors.forename: José Luis García
authors.initials: JL
authors.lastname: Ruano
authors.forename: Alberto
authors.initials: A
authors.lastname: Fraile
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Martín
authors.forename: Gemma
authors.initials: G
authors.lastname: González
authors.forename: Cristina
authors.initials: C
authors.lastname: Fajardo
authors.forename: Ana María
authors.initials: AM
authors.lastname: Martín-Castro
mesh_terms: D007546:Isoquinolines / Q000138:chemical synthesis* / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D011806:Quinolinium Compounds / Q000737:chemistry*; D013454:Sulfoxides / Q000737:chemistry*
chemical_list: D007546:Isoquinolines; D011758:Pyrroles; D011806:Quinolinium Compounds; D013454:Sulfoxides; C560364:pyrrolo(2,1-a)isoquinoline; C039109:isoquinoline; D009584:Nitrogen